High-temperature fan



Dec. 28, 1948. c. NYGREN 2457,255

' HIGH TEMPERATURE FAN Filed April 24, 1947 s Sheets-Sheet, 1

Viv/w Dec. 28, 1948. c, NY EN 2,457,2 5

HIGH TEMPERATURE FAN 6 Sheets-Sheet 2 Filed Aprii 24, 1947 Dec. 28, 1948; c. NYGREN HIGH TEMPERATURE FAN 6 Sheets-Sheet 3 Filed April 24, 1947,

Dec. 28, 1948. c; NYGREN 2,457,265 '7 HIGH TEMPERATURE FAN Filed April 24, 1947 s Sheets-Sheet 4 Dec. 28,1948. c. NYGREN' I 2,457,265

HIGH TEMPERATURE FAN Filed April 24, 1947 e Sheets-Sheet 5 mass c. NYGREN HIGH TEMPERATURE FAN 6 Sheets-Sheet 6 Filed April. 24, 1947 Patented Dec. 28, 1948 HIGH-TEMPERATURE Carl Nygren, Michigan City, Ind assignor to Michiana ProductsCorporation, a. corporation of Indiana Application-ApriLZl, 194-7 Serial-No. 743,51-6-- This invention relates to centrifugal ians or blowers for heat treating furnaces and has for its principal object to provide an improved an rangement and assembly of hub members and .bladeswhereby the latter are'securely made fast against outward movement under centrifugal 'force and .against turning movements with respect to the hub members that willsafely endure the rigorous conditions: of. service at high speed and high. temperatures.

Generally speaking, this is accomplished :by providing the blades with spaced legs which straddle a hub member having outwardly opening: notches. receiving the converging inner portions of the blades to effect a driving connection, and acircular series of fastening :means, suchas pins, make .the legs fast to the hub member. and

also center the shroud members.

Fig. 1 is a front view otadouble inlet fan'with the upper portion shown in section;

Fig. 2 is a side elevation of a double inlet fan, portions of the side pieces and blades being broken away;

Fig. 3 is a perspective-view of the cent'ralzhub member;

Fig. 4' is a perspective view of one of twelve blades used in the double inlet fan;

Fig. 5 is a perspective viewof-one-otZ liastening pins;

Fig. 6 is a perspective view of one oftwo hub collars;

Fig. 7 is a perspective view of meet two open side plates used in the double inlet fan;

Fig. 8- is a perspective View of a closed side plate, one of which, together with one of the plates shown in Fig. 7, is used in a singleinl'et fan;

Fig; 9 is a view corresponding to Fig. 1 of a single inlet fan;

Fig. 10-is an end view of the'hub'member'used in the singleinlet fan;

Fig. 11 is a view of one of two collars used in the single inlet'fan;

Fig. 12 is a view corresponding to Fig. '2 of th single inlet fan;

Fig. .13 is a perspective view of one of twelve blades used in the single inlet'i'an; and

Fig. 14 is a. perspective view of one of '25 pins used in the .singleinlet fan.

In the drawings, 1!]. indicates a hollow water cooled shaft for supporting and driving the .fan.

A hub member, generally indicated. by H in Fig. 3,.is secured to the shaft bythreekeys fitted inkey-ways l2 in the bore of the hub and. corresponding key-ways .in the shaft. Each hub member has an intermediate rounded flange l4 provided with notches -|5toreceivethe machined portions I-6- of the blades (Fig. 4) and form a driving connection with them.

In order to .reducethe weight of the hub, its

'7 Claims. (Cl. 230-134) diameter is reduced, as indicated at H, at each side of the intermediate flange l4, and this results in end flanges .i8,-each of which has 12 pin holes I'9 arranged in circular series to receive pins (Fig.5) for securing the blades and side plates to the hub member H.

Each blade (Fig. 4) has a body portion 2.I generally fiat and rectangular in shape,.,and integral with it. at the inner portionare legs 22' strengthened by vgussets .23 and provided with pinholes 2'4. to receive pins 20. Adjacent to their outer portions, each blade 21 has an overhanging hook 25 outwardly from machinev faces '26, and these cooperate with the periphery, of openside plates .21 (Fig. '7), which have notches 2,8 to receive the intermediate portions 29 of the hooks .25.

Each open side plate 21 is provided with openings 3'0. to provide inlets for the fan, which leaves spokes 3! connecting the peripheral shroud portions 32 with hub rings 33. The latter have twelve pin holes '34 to receive the pins?!) (Fig. 5).

The shaft 10 has a shoulder 35 against which one of two collars 36 (Fig. 6) is seated. The other collar 36 receives the thrust of a nut 31 threaded onto the shaft ill and made fast by lock nut 38 and lock washer .39.

From this description and the drawings, it will be apparent that the blades 2i straddle the hub member I4 with their pin holes 24 aligned with pin holesl 9. The side plates 2'! are on the outer sides of the blades and interengaged with the hooks 25, and have the pinholes 3t aligned with the 'pin holes 24 and IS.

The collars 36 are on the opposite sides of the wheel outside of the side plates 28, and their reduced pin holes 40 receive the reduced portions 41 of the pins 20 (Fig. 5).

The single inlet fan construction is similar in all respects, except that the blades 5! (Fig. 13), hubs 52 (Fig. '10), and shaft t! (Fig. 9)" are shorter. One side plate 62 (Fig. 8) has no openingslcorresponding to those shown at 30"(Fig. 7').

In the fan construction shown in the patents to 'NygrenNo. 2 1385,838'and Williams N0. 2,147,005, a Ianof 18 in-chesin diameter or lesshas so much machining that it throws the cost-of production out of line and really makes fans of those. sizes .toocostly.

With. the construction here illustrated, the

machining is confined .tosmall faces on the .legs

of the. blades, which can be done with a gang machine; the blade. slots and. the hub. .flanges, which can be done withan automatic machine; and the pads IE on the blades,. which can. also be done with agangmachine- Those-machined surfacesareall small. as compared with the prior constructions referred to- The principal object of the present -constructionds to. maintain the 1 dynamic/relation. between The arrangement of the pins in the hubs, the

legs of the blades, the side pieces forming the shrouds, and the collars establishes the dynamic relation between the parts that changes very,

little due to expansion and contraction. The nuts holding the collars in place are set up hard and then turned back an amount corresponding to the temperature at which the fan is to be used. For instance, in a 15-inch fan for working temperature up to 1600 degrees, the nut 36 should be turned back'about 9/10 0" at'room temperature to allow for expansion.

In the construction shown in Nygren Patent No. 2,385,838, the shrouds are carried by the blades. The present construction is distinguished from thatby the shrouds being part of side plates centered on the hub by the pins that establish the dynamic balance. I .The interlocking. relation between the outer portions of the side plates maintains the shrouds and blades in appropriate relation with great freedom in expansion and contraction.

The drawings show a construction for 15-inch fans with the double fan 8 /8" Wide at the periphcry and the single fan 3%" wide at the periphery. The intermediate flanges M of the hub member are 7" in diameter and slots are wide plus .001 minus .000, and the pads I6 on the blades are 1% thick plus .000 .minus .002. The pin holes 19 and 24 are in diameter reamed to plus .001 minus .000. The pins are .498" in diameter plus .000 minus .001, and the reduced portions ii 'are .436" in diameter plus .000 minus The side plates are made of mill fiat. The hooks 25 receive the edges with liberal clearance, and there is clearance between the intermediate portions of the hooks and the bottoms of the notches 28.

. The .specific features in the corresponding showing of the drawingsand the description, are

made iorthe purpose of fullness of disclosure in this particular embodiment, but are notintended to impose unnecessary limitations on the claims.

, I claim:

1. In a high temperature centrifugal fan, a plurality of blades in circular arrangement about a common axis of rotation with their outer portions diverging outwardly from said axis and their inner portions converging inwardly toward said axis and terminating in spaced legs, a hub member straddled by the legs and having outwardly opening notches receiving the converging inner endsof the blades to effect a driving connection with them, and means in circular series about the axis for making the legs fast to hold the blades against individual bodily movement outwardly due to centrifugal force.

2. In a high temperature centrifugal fan, a

plurality of blades in circular arrangement about member straddled by the legs and having outwardly opening notches receiving the converging inner ends of the blades to effect adriving connection with them, and means in circular series about the axis for making the legs fast to said hub member to holdthe-blades against individual bodily movement outwardly due to centrifugal force.

3. In a high temperature centrifugal fan, a plurality of blades in circular arrangement about a comon axis of rotation with their outer portions diverging outwardly from said axis and their inner portions converging inwardly toward said axis and terminatin in spaced legs, a hub member straddled by the legs and having outwardly opening notches receiving the converging inner ends of the blades to effect a driving connection with them, and pins in circular series about the axis for making the legs fast to the hub member to hold the blades againstindividual bodily movement outwardly due to centrifugal force.

d. In a high temperature centrifugal fan, a plurality of blades in circular arrangement about a common axis of rotation with-their outer portions diverging outwardly from said axis and their inner portions converging inwardly toward said axis and terminating in spaced legs, a hub member straddled by the legs and having outwardly opening notches receiving the converging inner ends of the blades toefiect a driving connection with them, pins in circular series about the axis for making the legs fast to the hub member to hold the blades against individual bodily movement outwardly due to centrifugal force, and shrouds centered by said pins cooperating with the blades.

5. In a high temperature centrifugal fan, 'a plurality of blades in circular'arrangement about a common axis of rotation with their outer portions diverging outwardly from said axis and their inner portions converging inwardly toward said axis and'terminating in spaced legs, a hub member straddled by the legs and havin outwardly opening notches receiving the converging inner ends orthe blades to, efiect a driving connection with them, pins in circular series about the axis for making the legs'fast to thehub member to hold the blades against individualbodily movement outwardly due to centrifugal force, shrouds centered by said pins cooperating with the blades, and collars engaging the shrouds and pins.

6. In a high temperature centrifugalfan,- a plurality of blades in circular arrangement about a comon axis of rotation with their outer portions diverging outwardly from said axis and their inner portions converging inwardly toward said axis and terminating in spaced legs, a hub member straddled by the legs and having outwardly opening notches receiving the converging inner ends of the blades to effect a drivingconnection with them, pins in circular series about'the axis for making the legs fast to the hub member to hold the blades against individual bodily movement outwardly due to centrifugal force, and shrouds centered by said. pins and interlocked with the blades. i

,7. In a high temperature centrifugal fan, a plurality of blades'in circular arrangement about a comon axis of rotation with their outer portions diverging outwardly from said axis and their inner portions converging inwardly toward said axis and No references cited. 

